This invention relates to a contactor and said contactor constituting a star-delta main circuit similar to a conventional three contactor system of wiring a combination of a plurality of contactors is provided as a structural member and an electromagnet is maintained in a deenergized condition at operation of the delta wiring. The contactor is composed of a case member, two electromagnets disposed at right and left on the lower surface of the case member, a traveling contact of slide metal system capable of bending in middle in each pole chamber, a stationary contact, two electromagnets disposed at right and left on the lower surface of the case, a pair of operation frames for rotary bending operation of the traveling contact, a metal cam for connection of the lower ends of the operation frames with each traveling iron core of the two electromagnets, drive springs disposed on the traveling iron cores of the two electromagnets and consisting of a plate spring for returning the traveling iron core from the stationary iron core when the electromagnet is deenergized, and a contact mechanism for causing the mechanical delta connection by the deenergization of the other electromagnet and holding the electromagnet in the delta wiring operation in the deenergized condition.
Heretofore, star-delta startings of a two-contactor system and a three-contactor system were generally employed as the starting system of motor, but the electromagnetic contactors available in market were of a one dimensional contact mechanism and were required of employing a circuit construction using a plurality of electromagnetic contactors star connection starting of star-delta, delta connection and contact for operation and for construction of main circuit. Particularly, the three-contactor system had a complete circuit construction and was capable of cutting a power source of the motor at operation stop, but an extra MMC electromagnetic contactor was required, and a considerable time and labor were required for wiring operation and mounting of equipment. Including a mounting area for equipment and wiring space, an accommodating area became far bigger, and sizes of cabinets or mounting boards tended to become big, resulting numerous drawbacks.
Moreover, during the operation of motor, the electromagnets are required to keep the energized condition, and long hours of sustaining such energization causes various troubles of adverse influences over adjacent equipment due to temperature rise or roaring, resulting in numerous drawbacks.